The present invention relates generally to quick connect and disconnect fluid couplings. More particularly, the invention relates to quick couplings that can be connected under pressure with minimal loss of fluid. The terms "quick coupling" and "quick connect coupling" are used herein as synonyms.
Quick connect couplings are particularly useful and well-known in the fluid handling art. For example, quick connect couplings are commonly used to join two or more hose sections together in a fluidtight manner. The coupling halves typically are designed to mateably lock together using a ball and detent mechanism that is secured by a spring-loaded sleeve, but the coupling can also be separated by a fairly small longitudinal force being applied to the sleeve.
When the coupling halves are unmated, either or both halves may be connected to fluid under pressure via the attached hose. Consequently, numerous designs for valve mechanisms have been proposed to prevent fluid transfer until the coupling halves are mated. Typically, each valve mechanism uses several parts including a valve member, a valve seat, one or more springs, body seals and valve seals. All of these parts must be carefully made to insure a good fluidtight seal under pressure. The large number of parts adds to the manufacturing material and labor costs, plus it can reduce the overall reliability of the coupling. Field repair of these valve mechanisms is also complicated, time consuming, and costly. While the various valve designs used commercially heretofore are generally acceptable in preventing leaks, the need has long existed for a simple, inexpensive and reusable valve mechanism for quick connect couplings.